Hi Kesaco and welcome to the forum!
Do you have any other USB devices (printer possibly) attached to the system and if so, do they work?
Does the flash drive light up when the drive is inserted?
If the system takes 20 minutes to boot I would suspect a virus/malware issue.
I would download, update and run MalwareBytes AntiMalware
Get the free versions
Do the full scans with both.
It could take considerable time so please be patient and let the scans complete
Edited by Eyesee, 25 October 2010 - 12:56 PM.