Something is going on. make sure you dont have any viruses or other bad-ware.
This will kill two birds with one stone:
1) Download System Rescue CD @
http://www.sysresccd.org/Download
2) Download Linux Live USB Creator (Lili) @
http://www.linuxliveusb.com/en/download
3) "Burn" The System Rescue CD .ISO to a USB thumbdrive or CD using Lili.
4) Reboot the computer with the disk in the drive to boot the System Rescue CD operating system.
(If it doesn't boot from the disk you will need to enter into the BIOS setup options and check the boot device priority to make sure the primary hard disk isn't the first thing its checking.)
5) You can format the problematic thumbdrive using gparted which can be found in the "Start" menu at the lower left corner.
6) You can run an anti-virus scan on your computer using clamav antivirus found in the "Start" menu.
7) Reboot the computer and remove the System Rescue CD disk and continue on with life as usual.