Web pages don't always load anymore

For the past few weeks we have been having trouble getting web pages to load sometimes. It seems completely random. A page will load fine one time than minutes later it just seems to hang up. The green bar starts moving then just stops. I tried re-booting my cable modem and router. I tried bypassing the router and connecting the ethernet cable directly from the modem to the back of the computer. I called my ISP and they had me run a speed test and said my upload and download speeds were what they were supposed to be. Curiously, they said they could see my computer but not the router (I had re-connected the router by this point.) The router is a Linksys Wireless G Broadband router, model WRT54G Version 5. My kids don't seem to have much problem connecting from their bedrooms with their laptops. This problem has gone from annoying to potentially a big problem, as my wife will begin working from home next week and has to have a reliable internet connection, as all of her work will be online. She wants me to rush out and buy a new computer. Our computer is seven years old, so I feel we have got our money's worth out of it, but I don't want to buy a new one if it won't help the problem. I also don't want to buy one in a rush without properly researching the purchase. I can't think of any recent changes to the computer that might have caused this problem. I am using Internet Explorer 7, AVG Free 9.0, and Zone Alarm 8.02.298.000. Below is some more info about my computer.

OS Name Microsoft Windows XP Home Edition
Version 5.1.2600 Service Pack 3 Build 2600
OS Manufacturer Microsoft Corporation
System Name YOUR-DC40AB16FC
System Manufacturer Gateway
System Model Thrasher
System Type X86-based PC
Processor x86 Family 15 Model 2 Stepping 7 GenuineIntel ~2399 Mhz
BIOS Version/Date Intel Corp. SR84511A.15A.0009.P01.0306260913, 6/26/2003
SMBIOS Version 2.3
Windows Directory C:\WINNT
System Directory C:\WINNT\system32
Boot Device \Device\HarddiskVolume1
Locale United States
Hardware Abstraction Layer Version = "5.1.2600.5512 (xpsp.080413-2111) "
User Name YOUR-DC40AB16FC\Owner
Time Zone Eastern Daylight Time
Total Physical Memory 768.00 MB
Available Physical Memory 388.91 MB
Total Virtual Memory 2.00 GB
Available Virtual Memory 1.96 GB
Page File Space 1.81 GB
Page File C:\pagefile.sys

Any advice will be much appreciated.

 

Well, we recently tried switching to Google Chrome as our browser and that seems to have solved the problem. I don't understand why, but I am just happy that our internet browsing works fine again. Thanks for the suggestions.