On every boot the event manager displays an error, as
follows:

Event Type: Error
Event Source: Service Control Manager
Event Category: None
Event ID: 7026
....
Description:
The following boot-start or system-start driver(s) failed
to load: MemAlloc

This has been happening over a long period of time (as far
back as the system log entries go).

I notice that at times the pc is quite sluggish
downloading webpages (compared to another one on the same
WLAN-DSL connection). Task Manager shows little CPU and
memory usage. Other times it is fast (not as a result of
caching, either). But otherwise pc seems to be normal.

Any ideas what this means/how to fix it?

Thanks...
Tom