somrscov - it sounds like you may need drivers but also more than that. Since you're dealing with an older OS (XP-Pro) you should get help from Microsoft.
here is a link to device drivers for XP
.Netframe is an essential systems execution software. It's needed to install some programs and/or run others. Plus Microsoft uses it for some functions on their sites. I think you're getting a message that says to install the 2.0 service pack - if so, you're going to need that - there's no getting around it.
AND IT SHOULD NOT BE REMOVED. There may be a problem with it but that can be fixed. The only time you should remove it is if you're installing a newer version - immediately. Make sure you get that service pack 2.0 or IF you're hardware can handle it download the current version of .Netframe
Here is .Netframe Link
here is link for XP How To's
You may need to install drivers for your graphics card like John said but it could also be the graphics card itself since this is an older, used pc. If I were you, I would be pretty mad at the seller unless he/she informed you of all these issues - because selling a pc that doesn't run properly or at least have all the components and drivers it came with - is BOGUS.
Make sure you have the correct SERVICE PACK installed you will most likely need to have Service Pack 3 on there but you can find that out at link above.
Finally, Make sure you have a legitmate XP OS installed on your pc. If you don't then GET YOUR MONEY BACK.