Useful, but full of the usual waste of time stuff that most hints and tips about PC Maintenance have.
I agree with the AV idea, I would highly recommended MSE as it consistently scores highly and has a very small resource footprint, you could also use Spybot and some other anti Malware software but as MSE uses MSes own Malware detection software and this software is often run as part of most Windows Updates it's a step that adds reassurance rather than a really needed extra layer of protection.
Backups and Restore points
Backups, yes, Restore points, no. Back in the day restore points where useful in the instance were you some how managed to totally balls something up, if you can balls up any installs on a Win 7 system to the point where you need to use a restore point then you shouldn't be using a computer. They also add the false sense that if you do get infected a simple restore will fix it, when in fact most Virus and Malware will by pass the restore feature.
HD Defrag, HD Error check, Reg defrag and Reg tidying
All of them are wastes of time, if you have some compulsion that forces you to install any and all software and then feel that you need to remove said programs within days of installing them then yes maybe you will see some benefit but most people will install a core set of programs and then will continue to use them for the most part, yes you'll try new stuff some will stay, some will get removed but here's the thing
1). A modern HD at 1Tb will cost £40 if you are filling that up with programs to the point that you need to un install stuff to make room then you have issues that simple HD cleanups won't help (Please note I said programs and not media as it is very easy to fill 1Tb worth of HD with Media but in that instance you would be better with a separate media drive.)
2). The time it takes to defrag a HD you will never make that time up with the reduced load times in your games, 20 minutes to defrag a HD so you can save 5 seconds loading a CS level? Really? You want to speed things up buy 8gig of RAM and disable your cache file. (The link is convincing but if flawed, it is a test to see how defragmentation affects a PC running Win XP in a corporate environment.)
3). Reg defragging and tidying sits with the HD space and the compulsion to install any and all crap, if you do what most folk do, run a core set of the same programs and only install and remove stuff as it comes up then you don't need to be messing with the registry. (Remember end of the day the way these reg cleaners work is by scanning the reg and then fixing the things IT thinks needs fixing, at best you'll waste 5 minutes and see no real improvement at worst you'll bork the registry and be unable to boot back into Windows.)
4). HD error checking is also a massive waste of time at least as a proactive measure. Windows has the ability to deal with duff sectors on your HD, most people will have duff sectors on their HD and never see any effect from it, if the condition of your HD is what concerns you then turn on SMART, Win 7 can then tell you the condition of your HD.
Cleaning the inside of your PC
Yeah go for it if you really have a compulsion to do light house work inside your PC, all you're doing is increasing the risk of ESD every time you stick something in there to clean it. Had 10 PCs over the years, four of them high end gaming rigs, never had to crack the case to do anything other than update hardware. If your PC is overheating as a direct result of dust build up then
a). Your PC was never heat stable to start with
b). Your PC needs some dust filters on the intake fans
I spent the next seven hours (four hours after my shift ended) reinstalling windows to customer satisfaction. Registry cleaners do not help, they are wastes of time and money.
What the five minutes to boot in to Command Prompt and do a copy of the backup file was too much?
Or failing that the reg can be recovered from command prompt using the recover tools that come with the XP install disc all of it can be done and dusted in ten minutes tops
Tech support finding the hardest way to solve the simplest problems.