It's not that hard.
17m is my record thus far. I'm prevented from improving my record by the fact they don't call me anymore.
Look, have you ever had to support someone over the phone with no remote access? Pretend to be that kind of user. 30 seconds of before saying you can't find the start bar, etc (oh wow, i've never seen that before! I just have shortcuts on the desktop!) etc etc etc.
Get indignant "I'm not supid!" if they give you foolproof step by step instructions and force them to do things the slowest way possible.
Anybody used to dealing with (l)users should be able to burn at least 5 minutes just GETTING to the event log in a way that convinces the scammer that your not being evasive, just utterly helpless. Misunderstand any instruction in any feasible way but don't get them frustrated enough to hang up.
When you get to the software bit, give him a 404 error at least once, and tell him he that's misspelt the URL he gave you. Then, in true user fashion gush that your trying to download it but your virus scanner is blocking it which is silly because it's obviously not really a virus and he's a nice man from IT and all you need is some help turning (pick random virus scanner your familiar with) off. Say it's asking for the administrator password and is it ok to put it in? Ask if the administrator password is "makesomethingup" which is used for everything else? Check with the scammer at this point that it is safe to reuse that password for everything including banking, isn't it?
I've never actually done one while sitting at a computer; if you are get the URL that they give you and submit it to all of the anti phising lines. Also, download but don't run the file and submit it to a couple of AV companies.
Claim you've run the program. If they put you on the spot and ask you what's come up on the screen claim either the application has crashed or the PC has, etc.
Stringing them out shouldn't be hard for anybody who's ever taken a helldesk call. Just mix and match the worst attributes of the worst callers that you can manage on the spur of the moment.