If your computer has become unstable, and unbootable because of malware. Or, if your pc won't boot after malware or virus removal, please use this forum.
Hm? You're right Amlak! That doesn't look right.
If your computer has become unstable, and unbootable because of malware, or if your pc won't boot after malware or virus removal, please use this forum.
That looks better.
Using a comma after a conjunction, which in the case above the conjunction is "and", is never wrong nor right and the ruling about when to use a comma before a conjunction in a list depends on whether you're following US or UK writing conventions.
The first sentence above ends dead at the word malware and should have a comma before the word "or", which is another conjunction that is used to merge the two sentences into one so it makes sense.
I'm certainly not an English teacher, but I had to take a whack at this!