Computer Won't Boot Up

Sorry, it is a put to gather computer running Windows 7 that has been running several months. I don't have the exact specs and currently cannot access them without access to the system. It all started with an error message cannot find file sendo. something or another (sorry cannot remember the exact error message) and the system deteriated from there; not being able to find drivers, strange crashes , then not being able to update or add drivers for New mouse and keyboards (tried several), games and other software crashing and stopping and finally full crash.

Sounds like a bad HDD. Boot into safe mode, and get a comand prompt (cmd), run chkdsk /r. it will say it cant do it while in use, so go ahead and reboot. It will restart asking you to abort check disk. Do NOT touch anything and allow it to run. After that, boot it back into safe mode, and get rid of all of your temp files, and such. Just do a general cleaning of the files. Defrag if it will let you. If you can boot it into safe mode, it might be a good time to go ahead and archive files onto another medium for safe keeping in case it is your HDD.