Hi, heavenstobetsy, and welcome to the forum.
Re the "
conflicting programs":
The general rule of thumb is that only one antivirus (resident) is installed at a time. Examples include Avast, Norton, AVG, McAfee etc.
You only have Avast, so that's OK.
(Proviso: Some AV's install deeply and need to have a particular tool run to completely remove them. Including Avast, actually, so what was the AV you used prior?)
You can also have one Antispyware running resident (which means realtime - scanning files as they write to the disk.) although you may get away with more than one. And you can have as many demand scanners as you wish to install.
If the scanners you have are the free versions, you're fine. The free versions are demand scanners. MBAM is particularly good. Another good one is Superantispyware. I would certainly look to replace AdAware with it. (Oh, that's right, I have.
)
You don't need a registry cleaner. They have their uses, but can sometimes cause problems, and usually don't speed things up much. Should you choose to try one out, I'd recommend a very safe one, like TweakNow. There is also a slightly more aggressive one built in to Ccleaner, an excellent disk clean program.