Windows 7 endless startup repair loop, no CDs available

Hello! Before I begin to explain my problem, I wanted to mention that I am essentially an average user without a significant background in diagnosing computer problems. I have attempted to scour the web for solutions to my problems but the problems themselves have changed often enough that I am completely lost at this point. I am hopeful that someone on this forum will be able to guide me to resolution, even if that doesn't mean I end up with a fully operational system.

Quick background: I bought my computer (Dell Latitude D830, Intel Centrino Duo processor) used from a fellow who refurbished older machines as a hobby. He sold it to me running Windows 7. I cannot recall which version it was but I think it was home or home premium, pretty sure it was 64 bit. He did not provide me with a copy of any software. It has been almost completely problem free until about 2 weeks ago. That day, when I turned the computer on it took something like 10 minutes to boot, and windows was very slow/delayed in processing the simplest commands. I ran a full virus scan, a malware scan, disc cleanup, and defragmenter and no problems were found. I learned about sfc /scannow and every time I ran it it found problems it couldn't fix. I ran checkdisc several times as well and it was always finding bad clusters and repairing them. The computer's performance improved incrementally but it kept trying to download and install the same updates over and over unsuccessfully, which slowed things down, so I turned off the automatic updater, and at last it operated like normal again, except that I would occasionally get error messages saying windows couldn't find MSVCR90.dll . A day or two later, the computer entered its current state of (non)functionality.

Now: When I press the power button, the Dell startup screen appears as usual, but it presents me with the choice to run startup repair or start windows normally. If I run startup repair, when it's finished it restarts and sends me back to the aforementioned choice. If I attempt to start windows, it restarts and sends me back to the choice. If I F8 and attempt safe mode, it restarts and sends me back to the choice.

I attempted to create the AVG USB rescue disc and was able to boot the computer with it, but the tool was useless as it didn't recognize the hard drive but could only scan or otherwise interact with the USB drive itself.

I'm prepared to accept the possibility that my computer is a total loss, as disappointing as that may be, but I would like to try to save it if there's hope. I have reached the end of my diagnostic powers and so submit myself to the wisdom of this forum.

I was able to check the HDD with Seatools and it declared the drive a failure. So, it is clear that the HDD must be replaced.

Is there any chance of rescuing files, or is it time to abandon ship?

Have you run Dell bootable hardware diagnostics from the F12 key at boot? If it will run it means the HD is not finished as lives on the HD, and will tell you the condition of all hardware. Otherwise confirm it with the maker's HD Diagnostic extended CD scan only.

You can try to rescue files from that step in Troubleshooting Windows 7 Failure to Start
which also includes everything that can be done to start Win7 if the HD is salvageable which if Seagate sounds like it is not. Did you run the Long scan?

If necessary to replace the HD the best upgrade one can have - faster than buying an expensive high end gaming PC - is to replace the HD with an SSD which prices are coming down to around $50 for 120gb. This is easy to do as most models have video tutorials you can google showing how, or its in the Manual on the Dell SUpport Downloads webpage.

Once the new HD is installed do a Clean Reinstall - Factory OEM Windows 7. Everything needed is in the blue link to get and keep a perfect install.

I apologize, I neglected to mention that the D830's factory installed OS was XP Professional. Consequently, I have no product keys or means of reviving 7 without purchasing a licensed copy (which I intend to do when I replace the HDD). Am I correct to understand that if I purchase a used copy complete with key, it must be a retail version in order to work?

I ran the long test on Seatools a few times. Each time it ran briefly, only a few minutes, until it had acquired >80 errors. Then it said it had "failed a diagnostic test" and gave me a warranty code. After that, it ran a DST scan which listed LBAs and repaired them but said the test was failed. I thought the results were confusing because it sounded like the disk was dying but not dead, however each new test found different problems than the previous. I wonder if the repeated testing did more harm than good.

I ran the diagnostics from F12 and when it tested the hard drive it gave me error code 0146 and said DST contains previous errors. All of the other tests passed. Web research indicates that code is for a dead/dying hard drive.

I have seen a few references to the possibility of booting the computer with Linux, using that software to find surviving files on the hard drive and exporting them to a USB stick. That is what I'd like to do, but the details of how it is accomplished are not clear to me. Where do I start?

Also, I have an OEM copy of XP for a compaq computer complete with all codes, etc. Would that be of any use?

To reinstall XP to the new drive you'd need to use your Recovery disks or find an XP Professional w/SP3 OEM copy to use with the Product Key on the COA sticker. If you download one online from a torrent be sure to read the comments to make sure no crack or anything else is added since you have a legal license key on the PC.

If you buy Win7 I would not buy a used copy or from any vendor other than a major tech site like Tiger Direct where we regularly see them for $89 for Home Premium OEM. Unless you know you need one of the expensive extra features in the higher versions, most consumers only need Home Premium. Compare Windows 7 Editions - Windows 7 Forums

Then follow the same steps to Clean Reinstall - Factory OEM Windows 7 paying special attention to how drivers are handled in Win7 which is different than XP.

For attempting file rescue you can use Peppermint3 - Create Live CD/DVD/USB To Use For Emergency Backup - Windows 7 Forums or Paragon Rescue Kit Free Edition 11.0 Free, or even the Win7 installation DVD to Copy & Paste - in Windows Recovery Console

Good news! I was able to access my hard drive and rescue the information I wanted using Knoppix Live. Dodged a bullet on that one.

Thanks for your help!