error in SVCHOST.exe

I am using Windos XP SP2, and a broadband connexion, few pages in IE OK and midway this error report generated and then IE, OE stopped responding.
Faulting application svchost.exe, version 5.1.2600.2180, faulting module netapi32.dll, version 5.1.2600.2180, fault address 0x0000a3c0..
Few seconds later a pop up error appear saying svchost.exe -Application error – The exception unknown software exception (0xc0000409) occured in the application at locaton 0x5b86a3co.
Please Help