Hey there, I have a toshiba A215, seems to be in the same series as it showed up with some searches of mine too.
First off you are going to want to run some serious virus scanning, download malwarebytes, ccleaner, and iobit advanced system care. Run malwarebytes full scan, could take a few hours to complete. If it finds anything with "registry" in its name or location, uncheck it, and install and run advanced system care, uncheck everything but registry fix, and run it. Run ccleaner and scan and fix the registry section several times(idk why, some items show up after you fix it again). Then run malwarebytes quick scan again and remove anything left that shows up.
Bad memory can wreak havok on a system, you can download memtest86 and put it on a cd, the test never actually stops, so I would let it just run overnight to see if it finds any errors.
More likely though, the PCB on the toshiba hard drives like to go bad, I had to scan the drive with CHKDSK 8 times to get the scan to even finish, windows will not boot up and attempts to copy the drive fail. This is because of a bad pcb, the person I bought it from said it locked up alot and booted slower and slower until it stopped booting at all.
The PCB for my drive (HDD2D60) 160Gb is $15 on ebay. Its probable that yours is going out on you, and you could probably find a new pcb for your drive on ebay pretty cheap.
I hope this helps you