Windows Vista Ultimate is great but now I'm really slow. What should I get to be up to speed?

OS Name Microsoft® Windows Vista™ Ultimate
Version 6.0.6000 Build 6000
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Name DH99YS61
System Manufacturer Dell Computer Corporation
System Model Dimension 3000
System Type X86-based PC
Processor Intel(R) Celeron(R) CPU 2.40GHz, 2394 Mhz, 1 Core(s), 1 Logical Processor(s)
BIOS Version/Date Dell Computer Corporation A03, 1/5/2006
SMBIOS Version 2.3
Windows Directory C:\Windows
System Directory C:\Windows\system32
Boot Device \Device\HarddiskVolume2


Locale United States


Hardware Abstraction Layer Version = "6.0.6000.16386"
User Name DH99YS61\Greg Lee
Time Zone Central Standard Time
Total Physical Memory 1,021.44 MB
Available Physical Memory 361.55 MB
Total Virtual Memory 2.45 GB
Available Virtual Memory 1.33 GB
Page File Space 1.50 GB
Page File C:\pagefile.sys

Thanks.