Here's my problem:

I'm attempting to restore an older desktop Gateway of mine, which is currently not functioning. It originally ran on windows 98, but i upgraded it to XP. A few months after the upgrade, messages appeared stating that if I did not call windows and register or something of the like, windows would cease to function in three days. I tried everything to fix this, even calling customer service, and now i wonder if it was possibly a virus. However, three days passed, the computer now refuses to boot up. I have tried using the system restore software that came with the computer originally, but there are continuous errors that will not allow windows 98 to reinstall itself. is there anything i can do to solve this problem? Advice would be much appreciated...

XP must be activated. You are usually given 3 days from install. Who did you call? Microsoft?

Is this a full version CD with Product Key? If so a call to Microsoft should fix that issue.

Otherwise:

Do you have a '98 disk? If so run Fdisk; format (which will erase all data) the drive and install '98.

How to Use the Fdisk Tool and the Format Tool to Partition or Repartition a Hard Disk

Fdisk Tool