I think if David Moyes receives no backing in this transfer window; either he'll walk away at the end of the season or the board will sack him in the summer.
He has the toughest job in football and in all honesty, the squad he was left with after taking over from Sir Alex wasn't the best despite United being champions. Last year they were pretty poor but managed to win the league by scraping wins and taking advantage of other teams inconsistencies. Ideally he should have been backed right of the bat in the summer but he missed out on several targets and only managed to land Fellaini at last-knockings at quite a hefty price. I don't think the board did enough in supporting him at this crucial time which lead to an 11th hour panic buy. I think they could have done with at least 5 players in the summer and really need that sort of volume this month if there is going to be any drastic turnaround in fortunes and to build on in the future. I don't think Young, Valencia, Nani, Jones and Cleverley are up to the standards despite winning the title 8 months previous and even the likes of Rafael and Vidic are performing well below-par. The magic of Fergie really grinded out success last season but it's proving a bridge too far for Moyes as the confidence and standard of football diminishes.
The remainder of the season along with this month will be crucial for the club. As it stands; they may not be in Europe next year. They desperately need rejuvenating and strengthening else they could sink and lose the likes of RVP and Rooney to rivals. Ultimately United need to get some personnel in this window and if they don't; it will suggest the future of Moyes is in question. Either he will lose faith or the board have no confidence and the rest of the season will be damage limitation.
The rebuilding should have started in the summer and that could prove pivotal if it hasn't already. The football isn't of a high standard, the results haven't been and the players have been well below par.