Not sure how to proceed

I'm trying to detemine what my grandmother did to her computer and I need advice.

I suspect she has some sort of malware on it. It's been running super slow (takes forever to boot into windows, open files, install software) and her AV software mysteriously disappeared either the day of or the day after she got cable internet. She's on an unsecured home wireless network and she lives in an apartment. She does have a firewall (Online Armor) but I don't know if it's configured securely enough. For all I know, it could be the firewall that's causing the slowness, I haven't been able to test it.

I tried to install her previous AV software (at her request) and it took forever to install (20+ min when it should've taken about 3 min). When I rebooted, the icons, taskbar, and start menu were not visible. I tried to end explorer.exe then restart it, but that didn't work. I tried rebooting, but it got hung up at the blue shutdown screen. I turned the computer off and left it at that point.

Her backup hard drive (D drive) is not visible in My Computer and I can't get it to come up when I type it into the address bar. I don't know if this is related to these other problems or not. It could be from a loose cable since she recently had the PSU replaced and moved to a new house (the computer wasn't packed very well).

I think the other computer on the home network has a browser hijacker or something, I'm not sure.

The slow computer doesn't seem to be able to boot into windows properly, so I assume I should try to boot into safe mode. Should I try the last known good configuration?

I don't know if I'll be able to install or run any anti-malware programs from safe mode.

She doesn't want to reformat if it can be avoided.

I'm not sure how to proceed. Suggestions?

 

It is not worth all of the time and trouble.

In my opinion, the best thing to do is to recover any important files using a bootable recovery disk such as Linux, reformat, reinstall, update, install all required software and then purchase and install an Imaging software and make an Image of the System Partition.

I think that Image for Windows would be a good choice since Imaging to DVD(s) makes the first DVD bootable. It should be quite simple to do a future Restores of the System Partition from the DVD(s).

 

A system restore from just before the problems started couldn't hurt. If that doesn't fix all the problems then if I were you, I'd run one of the livecd's for doing malware scans. Even if reinstalling the OS and her apps wouldn't take long, I'd do the scan anyway, just to try and find out how the problem started in the first place. If the livecd shows some malware, remove of that what you can. If that still doesn't resolve most or all of the issues, then you might want to try to repair the install using the original OS disk. Then you'll have to apply all the updates which can be time consuming.

You should probably copy what you can of the disk first, just to be safe.

Try the restore to previous point before the livecd. Some procedures like this may remove the restore points, so if you do the livecd first, trying restore will no longer be an option.

ps the advantage of a OS repair instead of reinstall is that you won't have to reinstall all the apps. If there are not many apps that she uses, maybe OS reinstall is a better way to go. Starting clean may get rid of a lot of old junk that doesn't get used anymore.

 

in addition to checking for malware also review event viewer logs for errors or warnings, in case they offer more clues on what is causing slowdown

 

Does your grandmother do anything that can't be done with a very user-friendly linux version like Linux Mint?

She can browse, have office apps, skype, listen to music, watch movies, do her online banking etc without any trouble.
She will only have to enter her password when booting up and when updating and that's about it regarding security.
No need for you, or her, to deal with an AV+FW/HIPS setup and regular scans.
Mint 9, based on Ubuntu 10.04 LTS will receive security updates for years.
Perhaps worth considering.

If she likes to stick to Windows, I'd do a clean install of OS+programs on a separate partition and make an image of it (with free Paragon f.i.).