Hard drive formatted. Problem solved. Thank you!
Well, apart from you having no OS on it, anymore, if that's as far as you went...
Seriously, formatting (or de-partitioning) and reinstalling your OS from scratch often[1] solves
whatever problem you have, and can't confirm that it was the SVCHOST causing problems. (Stakes to the heart tend to kill more than just vampires, etc.)
As such, do now ensure that your chosen AV is up-to-date and has a good reputation (often need not be a full paid-for version, I tend to find the "full suite" ones are bloaty, although they do offer additional tools and monitors to stop infection-vectors that you
might have been vulnerable to). Get Malwarebytes (my own preference, but other solutions can (and have) be mentioned) for periodic manual spot-checking. Separating system partition from data partition is
useful, as mentioned, but make sure you have some re-partitioning software (something like a GParted bootable CD, perhaps?) because at some point you may discover that you want an extra few gigabytes on your system area[2] that you want to take from your data area, or vice-versa, however well you thought you'd budget it beforehand.
One of my more diverse machines is a dual-booted Linux/XP machine, each 'system' on their own partition, with a third partition (NTFS format, readable/mountable by each OS) where I store stuff I wish to share between both boot-ups (really ought to get into Virtual Machining so that I can work on multiple OSes at the same time... Or set up that network file server I keep promising myself). Although I still keep my default Linux $HOME on the ext3/4/whatever Linux partition for more natural 'native' management. Not that you need to know this.
Technically, I should be splitting part of the 'system' partition off to hold the official /home part (thus saving me the same trouble as being advised about your Windows install, should I ever need to reinstall the system), but I tend to have historically gone for a single partition for all of Linux (to avoid the partition-resizing issues that I've just been explaining how to deal with!) and rely on backups to secure me whenever a reinstall is pursued, and/or
needed.
But I've a feeling that last paragraph isn't of any use to you. I suppose it's mostly there to show how inefficient I can be, in a self-effacing manner to those that know the better practices, however good my actual intentions are.
[1] Ignoring particularly resilient boot-sector infections that your reinstall doesn't touch, but those are rare enough.
[2] While you
can install programs to "D:\Program[ File]s", instead of the C:\-based location, if you're reinstalling the OS you'll often lose all the registry entries as well, so apart from truly stand-alone programs like DF/LCS you might as well just use the System disc for that (perhaps automate the backing up of save-games), but shift your Documents And Settings/whatever to be onto the D: (Data) partition drive.