As a "business", one person who regularly does this told me that it must be a 20 minute fix or he reformats and reinstalls. Assuming of course that it's a software issue. And his clients seem to be ok with reinstalling everything.
At first I was appalled but after having done a few, it's the only way to make any money doing this if this is your business. If it's not a quick fix, you'll waste all your profits away.
I ran into this and it was one of the reasons I got out of this work.
I found that most consumers and small business customers are incredibly stupid about their data and they don't respect it until it vanishes, then they bawl like little babies, and this after you told them that they will be screwed if they don't protect their data.
You're supposed to do everything for about $100.
In particular almost no home customer will pay to protect or recover their data in an extreme situation. I also found that almost all PC crashes or problems that result in a non bootable PC are extreme situations, IE, if you follow the product instructions and use the system recovery procedure, you format the partition and lose all of their data. Almost every crashed or virus ridden PC requires a lot of work and trial and error to recover the data reliably.
I also found that a big red stupid bit comes on in the general public when you try to describe what they can expect if they lowball the repair.
I once had a woman call me who was beside herself because her computer was trashed, and she had purchased a new computer, but she did not have backups. She did believe that her pictures, business records, etc were intact on the crashed system.
I told her I would charge her $200 (!!!) to drive out to her location, pick up her system, recover the data, and deliver the system back to her with a set of backup DVDs containing her data.
Note to everyone if you hadn't caught on, I was probably pricing my services at $50 an hour or less when you take all the time into account.
She acted like this was a fortune and said she really didn't know and she'd have to talk to her husband (sexist remark here: I got that "I need to talk to my husband" from several women who balked at my prices.)
The offer didn't stand, of course, I never heard back from her. I had like experiences with several customers. I'd bend over backwards to recover their data and they acted like I was ripping them off.
Most PC owners are "People of Wal-Mart" in every respect. Backward, cost paranoid, and really stupid. The "aware" are a tiny minority of the public.