Would too much mail in Outlook Express affect it's performance?

My wifes computer is bogging down bigtime. Outlook has done it's compacting reminders. She prob has 900 in the inbox and 500 messages in folders. I was wondering if the amount of content affects its performance, messages slow to open. I've done some basic cleaning of the entire system, but wonder if it may be something else. She just had some malware removed a few months ago. I will prob install CC cleaner on it tonite and go from there. Seem logical?

 

Hi there:

I use Outlook Express and presently have 1456 messages in my inbox of which 340 of them are unread. I archive my emails into several folders and have migrated those email to every new computer I get. I have been doing this since 1999 or so. I'll screen shot my directory mail to show you, but have not been bogged down with the amount of mail yet. However, ever so once in awhile, it will prompt me to compress(?) those email, which I do. Doing this (on my machine) will take over half an hour, so I usually let it do it on its own, and head into town for a coffee. But unless someone a little more saavy comes along and says otherwise, I personally do not think that having the amount of email you have, will bog down your machine.

(I uploaded 3 of my 5 screenshots. The post will only allow for the first 3)

 

Now just to be clear is the computer running slower or is it just outlook?
The amount of emails (imo)has no effect on how outlook performs. In Outlook or outlook express once the emails are downloaded they sit until such time a command open, delete, move is given. Outlook only cycles when you hit send and receive then it springs into action. Messages can open slowly when there are large files attached to them and send and receive can be slow if there are a lot of messages to download, large files or it cycles through numerous accounts.
You also mentioned she had malware on here system. I would go to the malware forum just to check to make sure it was completely removed.

http://forums.majorgeeks.com/showthread.php?t=35407

 

Just from my observation 900 emails in the inbox slows Outlook Express considerably. My Dad used to keep a couple thousand emails in his inbox and I was always annoyed at how slow his OE performed.

Lots of email in OE should have no effect on the whole PC when not using the program.