He is probably right. But it could be difficult to track down. Trial and error.
Run a full AV scan and a "Malwarebytes scan".
Make sure you are not overheating ("Speedfan")
"WinPatrol" also lets you do similar. More options.
- wait for more responses here
- badger your Uncle to come and fix it?
Cost you dinner and beers?
Did he leave you a Vista setup disc?
Repair download disc is here. It is not an OS install disc.
Don't do any recovery/reformat if you haven't got everything backed up elsewhere. Just repair.