|Try System Restore.|
All Programs - Accessories - System Tools - System Restore - Pick a date before your trouble started. and than run your antivirus and Malewarebyte Anti-Maleware.
You can run Error Checking.
1. Error Checking- Don't force a stop. 4 & 5 takes the longest.
Start - my computer - right click local disk (C) - properties - Tools Tab -
Error checking section - Check now - check mark both boxes - Start -
This requires a restart to begin.
2. Start - Run - type - sfc /scannow - OK
Don't forget the space between c and /
You may need the Recovery CD if any thing is found wrong.
Don't insert unless asked for. Takes about 35 minutes.
If none of the above works try Last Known Good Configuration
by = Power on = Start tapping F8 key.
After selection click Enter.
It pays to have a backup system like Acronis True Image
to restore your hard drive if needed.