disk check constantly running on boot

hi guys, I have a PC in the house which runs vista and recently it has been insisting on performing a disk check every boot. can anyone give me any hints as to what is going on and how to stop it.
i have been advising a reinstall of the OS but the owner seems reluctant, are there any steps we can take before that

i have found an event logged on the disk saying the file system structure is corrupt and unusable, i am going to attach the last 2 days error logs asap

Hey, try this : http://www.vistax64.com/tutorials/91467-startup-repair.html
or this : http://www.vistax64.com/tutorials/66978-system-files-sfc-command.html

ok well i'll get to work trying them but in the meantime here are the errors for the past 48 hrs

Do a check with your anti virus program with updated data base, and do this please. Check for malware with this , Free . : Malwarebytes : Malwarebytes Anti-Malware PRO removes malware including viruses, spyware, worms and trojans, plus it protects your computer , do full scan and make sure those are good..Lets see what we got going on at this point.
Maybe a DNS flush would work. dunno yet. : http://www.vistax64.com/tutorials/74209-dns-resolver-cache.html

Nine out of 10 times that warning is a precursor to drive problems.
Back up your stuff, as a precaution and then test your drive

Test Hard Drive

Hard drive scan usings SeaTools - SeaToolsfor Windows | Seagate - Both long and shorttests

Go ahead and disregard my instructions , and do what Rich has suggested. I have no idea what i was thinking there. I am a newbie .