Avast error-system restore

[avastuser196]

I am an avast user (v.5.0) and recently a duplicate file deleter was run (with permission) on my computer that deleted all duplicate files in the system. I found that it had deleted duplicates on the desktop and all over the place so I did a system restore to the day before. I finished system restoring and when the computer started up again, I found that Avast was not working (according to the Windows Security Center). I clicked the "turn on" button and pressed continue, run, etc. and a message box came up that said "File system shield provider not found". I cannot seem to turn Avast on.

[Gargamel360]

This was just discussed earlier, here and elsewhere, see: http://forum.avast.com/index.php?topic=58973.0
Seems touch-and-go, some users report problems, others not.
Did you try a simple reboot yet? (no offense, but many seem to not consider this)
You might also want to try a repair, go2 Add/Remove, click on Avast! then Change/Remove (or uninstall/change, depending on op system), choose the repair option then follow the steps.

[avastuser196]

Reboot didn't solve it...if I reinstall it will I have to purchase it again?

[DavidR]

No you won't have to purchase it again.

You did save the email with the license information and also the license.avastlic file (used to register your avast version) ?

[avastuser196]

Where should I download it? If I download the trial version is there a place where I can enter the access key from my email? (the first one I got before it stopped working)

[Hermite15]

Where should I download it? If I download the trial version is there a place where I can enter the access key from my email? (the first one I got before it stopped working)

just like you did last time you installed it

[DavidR]

Where should I download it? If I download the trial version is there a place where I can enter the access key from my email? (the first one I got before it stopped working)

How to register avast 5 pro on page 7 - 8
http://files.avast.com/files/documentation/quick-start-guide-pro-en-ww.pdf also see http://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=459.