explorer.exe and vsmon.exe using more and more memory.

Hi!
I'm having a very weird situation here.My total memory on my pc is 512mb and lately when i go to the windows task manager i can notice that explorer.exe and vsmon.exe(True vector for Zone Alarm)increase in memory consumption,this happens only when my pc remains on for more than one day(like now it's been on for exactly 1 day 22hours)and explorer.exe is 51,344k(approx.25,000k when just turn pc on)and vsmon.exe is 41,564k(approx.18,000k when just turn pc on).

My problem is that due to these high memory consumption some programs that i wish to run show sign of slowing down(nero for example)and even worst,if i want to burn anything i'm afraid there won't be enough memory available for smooth burning.Anyway i'm looking forward to upgrade my memory on my pc soon or later but for the time being this is giving me a real headache!

Can anyone please explain to me why explorer.exe and vsmon.exe keep on increasing their memory consumption mostly when my pc remains on for a long time?

Does it have something to do with the new firewall(zone alarm)that i just installed recently?I,ve opted for ZA because it is said to be much better and safer to use than the normal windows firewall and also it's better to use firewall like ZA when use any P2P progam.Now it may only be a pure coincidence,i don't know because i'm still a beginner about pc stuff,so that's why i'm turning to any of you guys or gals who can help me about that,i will be very thankful for that.


Thanks.

Vincent.