|"thermal operation" says "overheating" to me. Sounds like it overheated and might have fried one or more components.|
To fix the problem, do this:
1. Open the case, blow out the dust. Use canned air.
2. Power on the computer, make sure ALL fans are spinning.
3. Power on the computer and listen for beep codes. If the computer doesn't start, post a follow-up and tell us what beep codes you heard. Need to know how many beeps, whether they are short or long, and in what order.
4. If the computer does start, post the full, exact wording of any error messages you get.
Do all that and report back on the results.