Lots of problems and can't re-install

Sounds like your system is at SP1 level and your DVD is at pre-SP1 level. Then there would be a compatibility issue.

You can try to download and burn a SP1 level version from here. Roll down on the webpage until you get to the English versions.

If you do not have a Windows 7 installation DVD, or it's not up to the current service pack level, you can download a legal copy with SP1 integrated from here:

Windows 7 Direct Download Links

Make sure you get the same version you have, Home Premium, Pro or Ultimate and 32 or 64 bit. Note that Basic or Starter is not available.

I recommend using ImgBurn at 4X speed (or the slowest available) to create the DVD from the downloaded .iso file.

You can do this on any computer capable of burning a DVD.

YOU MUST HAVE A VALID KEY TO INSTALL THIS .ISO. The one on the COA sticker on your computer will work.

You can also create a bootable USB Flash drive (4GB or larger) to install Windows 7 from.

1. Download and run Universal USB Installer – Easy as 1 2 3
2. Select Windows 7 from the first drop down list, all the way to the bottom
3. Select the downloaded Windows 7 iso file
4. Select your USB flash drive
5. Click Create

For techies or folks who work on computers: Create Windows 7 Universal ISO With All Editions Selection On Install with ei.cfg Removal Utility.
This will fit on a 6GB flash drive or can be burned to a DVD.