System restore is only going to work for a small percentage of users following this.
Most users system restore points have been flagged as viruses, so are disabled.
Best strategy is to maintain good backups, preferably by use of an imaging program.
The OP was fortunate that system restore worked in that case.
Anyone who wants help getting something working again would be best advised to start a new topic. Please include your OS (including SP) and the symptoms of what is wrong.
As a general guidance, which may fix a lot of problems,
-Make sure the VPS is up to date,
-Start Avast, open the chest to the "infected files" section, only. (Default.)
-Right click each infected file, select "rescan".
-If it rescans clean, right click it again, select "restore".
A reboot may be required.
If those steps do not work, please start a new topic. It's too hard attempting to help many users on one thread. Just gets confusing. I'm sure you understand.