Can Brown still hold a March 25th Election?

The simple answer is, yes. Here is the timetable from the official Commons’ Briefing Paper, together with the relevant dates.

Proclamation summoning new Parliament/dissolution of old Parliament/issue of writ
Day 0
Monday
March 1st

Receipt of writ
Day 1
Tuesday
March 2nd

Last day for publication of notice of election (4pm)
Day 3
Thursday
March 4th

Last day for delivery of nomination papers/withdrawals of candidature/ appointment of election agents [...]

Latest Forecast - 15th January 2010

Forecast UK Tracker

This is the latest of our new style General Election Predictions, focussing on projecting forward to the upcoming national vote. As political events settle down after a dynamic fortnight, Labour have pulled back slightly but still look set on course for a disastrous defeat at the polls.
Summary

Party
%
Since 2005
Since Prev

Conservative
39.2%
+6.8%
-0.8%

Labour
27.7%
-7.5%
+0.5%

Lib Dem
19.8%
-2.2%
-0.1%

Swing Labour to Conservative
[...]