|Sounds like one of two problem.|
1. Your system could be overheating. Are all the fans running? On a laptop most of the time the fans can be seen someplace. You should be feeling some air flow.
2. Your power supply could be going, though typically for these you can turn back on the system immediately, not after a while. But I've seen the latter on rare occassions.
As for the fingerprint reader, you should be able to go into Add/Remove programs and remove the fingerprint reader software.