Windows won't start

I have a 6mth old HP ProBook 4740s 64bit W7 Professional i5. I've never been overly happy with it. It often takes a while to both start and shut down and recently I noticed that memory usage was high using the desktop gadget. When I checked the system config advanced boot it was only using 1 processor and 218 of RAM I was advised to change it to 4 and 4096 RAM.

Now I can't get windows to start. Is it because of what was changed? I did remove some programmes from the start up menu but nothing important

It's always been a bit backwards at starting whereas all other PCs I've had start windows then asks for the password this pc asks for the password and then boots windows.

It's run a auto repair but says it can't fix the problem the only error it comes up with is 0x490 it does give a few options system restore being one but as you see from my thread here I could never get it to do one System Restore not saving?
another option is to use the backup disc I made but yes you've guessed it i can't find it!!

I googled error 0x490 and found this System Recovery Options but I can't get to the advance start window again.

Is there anything I can do or will I need a professional repair?

Thanks so much for your help - the version I require I believe is the forth one Windows 7 Professional x64 SP1 U remedia fresh. Tho' I'm not sure what the U remedia fresh is.

How does this download work? I assumed it would go into my download folder and from there I can burn it to disc however it seems to to be saving in google downloads can I burn it from that location as it's a new one on me?

Thanks - this what has happened so far....

The first thing that always happens under normal operation is it asks me for my password - then windows starts-

Now when I try to start after 30 seconds or so it's going back to the password screen, I type it in a second time hit enter and get a screen [black with writing] that says 'Windows failed to start' and asks if I want to try to start windows again normally or do an Auto fix. At the end of the auto fix there are 2 links one is the log of what it's checked and where I found the error 0x490, the other link asks what method I would like to try to fix the problem they are:

Start up repair [already tried]
System Restore [would never do one]
System image recovery [Can't find it - very puzzling]
Windows memory diagnostics
Command prompt

I can't get it to recognize the Iso disc or find any way to open the disc.

I think I'm stuck!!

OK

I press the start button it asks me to login -that's usual

It goes to the windows screen and after a few seconds asks me to log in again

The 2nd time I do I get a black screen telling me there is a boot problem and it runs the auto recovery.
the auto recovery tells me there is a problem and give me 2 links - 1 tells me what has been checked the other gives a list of options as in reply 5.

I downloaded the ISO file [almost 3GB] the copy utility wouldn't allow me to burn to disk it told me the file couldn't be found so I used the W7 utility.

When I put the disk in nothing happens with it, how do I make sure it tries to boot from that and not HDD? I don't get anything on screen other than what I have said above no prompts etc.

I downloaded imgburn and burnt a 2nd dvd. My pc booted from it and I set the language time etc as asked I then clicked repair install.

It went through the motions and but came up with the same options I had before, basically 'Start up repair cannot detect a problem' [the original error 0x490 has gone] and gives me the option to finish [shut down] or cancel [that takes me back to the install repair screen].